In an excellent article in Scientific American, Virginia Sole-Smith discusses age-old taboos against menstruation which have led to a lack of research on how women’s cycles work, resulting in serious consequences for their health.

In their quest to bring reproductive freedom to women, scientists figured out how to supplant periods long before they tried to understand why they work the way they do.

Sole-Smith notes in her article, “Menstruation is essential to human reproduction and therefore survival. It is also one of the biological processes that makes us special because humans, chimpanzees, bats and elephant shrews are among the only animals on earth that go through it. The vast majority of mammals signal fertility through estrus, the period when females are ovulating and dis­play their sexual receptivity via genital swelling, behav­ioral changes or pronounced alterations in body odor. The female human body, however, conceals this critical window. Instead our most visible sign of potential fertility is menstrual blood, which, ironically, appears after the fertile period has closed. The endometrial lining of the uterus thickens over the course of a woman’s cycle as her estrogen level rises. If none of the eggs she releases at ovulation joins with a sperm and implants in that lining as a fertilized zygote, then levels of estro­ gen and another hormone called progesterone drop, triggering the uterus to shed the thickened endometri­ um so it can start fresh in the next cycle.”

I wanted to share one of the data visualizations from her article depicting the menstrual cycle. The dataviz shows time (28 days), thickness of the uterine endometrial lining, concentration of hormones released by the ovaries, the ovulatory cycle, and concentration of hormones that stimulate the ovaries over the 28 day cycle.

Sole-Smith’s article is important because it addresses a topic we tend to avoid in society, how a period has been perceived culturally and historically, the cause and effect of the introduction of birth control, and finally, how men have historically controlled the discussion and funding of research surrounding the menstrual cycle and women’s heath in general.

I highly encourage you to purchase a copy of this issue of Scientific American (May 2019), and read this important article.